Containment procedures:
SCP 3653 is contained within a 5m by 4.5m by 3m container made of
1.125cm thick steel. Door to container is .7 by 1.6 meters and requires
6 digit passkey and level 3 level 4 keycard to unlock. lock mechanism
for any future container must be electromagnetic attachment.
The container for SCP 3653 must be suspended 25 meters from the floor
and ceiling of the room, on steel girders at least 785 cm across. annual
maintenance must be done to fix warps in the suspension and/or enclosure.Under no circumstances should any unauthorized objects be within
a 25 meter vicinity of SCP 3653.
There must be a catwalk to access the container door made of lead gilded
Steel. Container is currently within a room which requires two agents,
and one level 4 personnel at control and one agent at the entrance, within heavy
containment zone.

Description: staircase that changes its own size and that of any
objects on it relative to each flight. Each flight up is ten times
larger than the previous flight, each flight down is 1/10 the size.
The staircase appears to be much larger than the shack it is
"inside". the sides of the staircase seem to be lined with an
invisible wall.
After each flight there is a plaftorm which rotates the staircase
by 90°.
On each side of the staircase there are invisible walls which prevent
from reaching over the side. The walls do not appear in any wavelength
of electromagnetic radiation observed(see experiment 5). Within
SCP 3653 there are no visible objects besides the staircase,
SCP 3653-A, and SCP 3653-1.
Objects in the region within 25 meters of SCP 3653 will become
misshapen and warped. Within regions closer to the SCP they
become misshapen at quicker rate.

Discovered ██/██/200█
After reports in ████████, New York of several civilians coming out
of the nearby forest in a gawked/terrified manner speaking of things that
were "not belonging in this reality" a foundation agent took notice.
█ agents were dispatched disguised as wildlife management services
into the forest. The team found a cabin ███ meters away from
█████████. The flora near SCP 3653 appeared misshapen and was dying.
The cabin had unusual properties as it was indestructible,
even though it appeared to be made of wood. when agent ██████
opened the door to SCP 3653 he expressed [DATA EXPUNGED].
It took ██ months for a window to open to move SCP 3653 to site 19.

Addendum A

Because of SCP 3653's properties, several experiments explorations, and interviews of SCP 3653-1 have
been conducted.

Experiment 1 ██/██/2009

Experiment 2 ██/██/2009

Experiment 3 ██/██/2009

Experiment 4 ██/██/2010

Experiment 5 ██/██/2011

Interview 1 ██/██/2011

Exploration 1 ██/██/2012

Exploration 2 ██/██/2012

Exploration 3 [DATA EXPUNGED]

[DATA EXPUNGED]

Addendum B

Along the sides of SCP 3653 there are to scale representations of
several objects of various sizes (SCP 3653 A) including:

Microbes
insects
marbles
hair
mice
molecules
etc

These objects seem to levitate beyond the walls of SCP 3653.
SCP 3653-A will not change size relative to SCP 3653.

Addendum C

psychological effects.
SCP 3653 causes observers to feel a sense of terror and
become overwhelmed with confusion and hysteria.
This causes subjects to be strongly inclined to exit
SCP 3653.

Addendum D

Within SCP 3653 resides SCP 3653-1. SCP 3651-1 Appears to be a
humanoid figure approximately 221.3 cm tall with unkown mass.
It is seen wearing a black lined suit with a black tie and
black pants, each of unkown origin. The facial features of
SCP 3653-1 resemble that of a pale adult male of approximately
60 years of age. SCP 3653 claims to be the creator of
SCP 3653.
When SCP 3653 is asked about it's origin or is asked to exit
SCP 3653 it becomes hostile for 150 seconds and begins [DATA EXPUNGED]. SCP 3653-1
will not pursue subjects outside SCP 3653.
When SCP 3653-1 becomes hostile the door to SCP 3653
shall be closed immediately.

Addendum E

At the presumed lower end of SCP 3653, 35 flights down is a solid black wall. (SCP 3653-B)
Every 1-2.5 seconds semi transparent protusions briefly extend from SCP 3653-B.
Any object that crosses SCP 3653-B explodes at a magnitude of 10000 psi.

SCP 3724

"horse with no name"

Object class: Keter

Special Containment Procedures:
SCP 3724 is to be held in an airtight, foam padded 10x10x5 m steel vault 3.125 cm thick.
Door to container is 1.43 by .7 m in dimension with double electromagnetic
lock mechanism. Container is to be suspended on four large springs on
the lower four vertices of the container. 2 guards are to be stationed at the control and
2 at the entrance.
Admittance to room and container requires level 4 clearance and 8 digit passkey.

Description
SCP 3724 has the appearance of a large brown horse weighing in at 300Kg.
SCP 3724 often maintains normal habits of a horse. However, when
any human subject attempts to call it using a name within 20m, SCP 3724 will
become hostile and attack the exact subject which spoke.
While this happens, SCP 3724 will grow twice its size and grow a
long, semi-reptilian mouth, which it will use to gnaw at its victims.
SCP 3724 will only refrain from its hostility after the victim has been killed.
SCP 3724 does not seem to attack audio devices calling it.
Further testing is ongoing.

SCP 3724 was discovered in an abandoned farm in █████████ Ohio. After reports
of several adventurous people going missing in the area.

SCP XXXX

Object class: Keter

Containment Procedures
SCP XXXX is to be held in an airtight, 7.5x7.5x3 meter steel enclosure. The walls, ceiling, and floor of SCP XXXX"s enclosure are to be 32 cm thick. The entirety of SCP XXXX's enclosure is to be airtight, soundproof, with lead & asbestos lining beneath the visible walls & ceiling of the enclosure. The entirety of the enclosure and enclosure entrance is to be completely sterilized with a thin film of bleach or other toxic material on the walls and ceiling/floor of the enclosure (exception being the center elevated floor; see addendum D) . A new film of the chemical must be sprayed every three days to prevent any form of organic material being present. SCP XXXX's enclosure must have high power Halon system for activation at any given moment, as well as a constant flow of chlorine gas in the chamber. SCP XXXX's chamber must have an air pressure of no ore than 620 millibars and a low (7.5%) oxygen concentration. All previously mentioned ventilation/gas flow related systems must not be connected to outside systems but be supplied with tanks within a chamber above the main enclosure. The chamber must be kept at 268 degrees kelvin at all times. The Site room designated for SCP XXXX is to have concrete walls and floor of thickness no less than 875 cm. The entrance to SCP XXXX"s enclosure is to have a triple door corridor with password, keycard, and control override, with level 4 clearance. The lock mechanism must be a double electromagnetic/piston locking mechanism. The enclosure must never have any windows, and the only way to monitor SCP XXXX's behavior is with monitor cameras. There must be a 2 permanent guards at control, 2 at entrance and one permanent level 4 personnel at watch. Under no circumstances should SCP XXXX's enclosure have more than one door open at once. If SCP XXXX
is to ever breach containment, its current site is to be considered condemned and on site nukes are to be detonated.

Description

SCP XXXX is a presumably liquid metal like sphere 40 cm in diameter. It is estimated to be 80 Kg but its mass slightly changes at different periods. It constitutes of an unknown metal like material. SCP XXXX will roll across surfaces as if solid, but appears to be capable of changing its shape and viscosity to move through obstacles such as grates. It is unknown how SCP XXXX is capable of producing motion and changing its own material properties. SCP XXXX Appears to be slightly magnetic and efforts to create use of magnets to restrain SCP XXXX is underway.
SCP XXXX is extremely hostile and will attack any qualified victim within 20 meters. The specifications for qualification are the presence of a nervous system in their bodies, regardless of the type. SCP XXXX does not seem to regard the size of the victim or their nervous system (Ex: SCP XXXX has attacked tardigrades and other such organisms showing no differentiation for its size; see experiment IV). SCP XXXX will engulf the victim's head or head like appendage and retain its position and spherical shape until it is smothered. SCP XXXX retains its volume regardless of the victim's size therefore if the target is small enough it may engulf their entire body. On the other hand, if the target's head is very large, it may be unable to smother it. This is because of the inability to retain a constant volume while retaining a spherical shape around the victim's head regardless of the shape and size. It will either be stuck in that position until the victim dies from other factors or is forcefully removed (in some certain cases, victims of SCP XXXX may be killed by on site agents to return it to a dormant state).

Addendum A

Addendum B
SCP XXXX in liquids
SCP XXXX's material properties change when in liquids though the exact change depends on the liquid's viscosity, density, and other chemical properties.

Water

When submerged in water at 285.2 degrees Kelvin, the following occurs:
SCP XXXX will drop into the tub with no visible effect initially. It will become more sluggish than when out of water. It appears to suffer from portions warping and ruffling. Stays intact.
275 Degrees Kelvin:
Similar to previous with more visual effect.
374 Degrees Kelvin (Boiling):
Does not appear visually effected other than change in heat and lower viscosity.